A type of electrical connector widely used in interconnecting electrical and electronic devices employs a thermoplastic material sufficiently resilient to incorporate in one piece bores or cavities to receive contacts and hinged elements to facilitate latching and fastening of connector halves together. Such connectors are used in high volume and accordingly, are made in multiple cavity molds with mold cycle times as short as possible, consistent with the material employed and the need for minimizing distortion in dimensions to acceptable tolerances. One of the practices widely utilized in molding such housings is to maintain wall thicknesses throughout the connector relatively constant. By that is meant that wall thicknesses varying much more than 50 percent through any section of the connector between mold surfaces, between an outer mold shell and core pins, may experience not only distortion, but tolerance variations and a visual appearance, which is unacceptable. Longer mold cycles may remedy some of these shortcomings, though not all, and will lead to a substantial increase in cost of housings.
With respect to one widely used type of thermoplastic housing, the interior bore of the housing has been made to include a contact receiving sleeve that forms a bearing segment to support the contact radially within the housing, the sleeve thickness being made along most of its length approximately equal to other wall thicknesses of the housing. This interior sleeve typically includes an inwardly directly beveled or tapered surface that serves to guide contacts during insertion of such contacts within a housing. With respect to male contacts having a rounded forward end, such sleeve works generally adequately without stubbing, but with female contacts that have a blunt or squared end, problems have arisen due to stubbing with the female contact catching on the end of the sleeve if the sleeve is not adequately concentric or if the contacts is not properly lined up. This sort of problem is aggravated by a lack of concentricity of the sleeve caused by high speed mold cycles or variations in plastic material. At one time the contact bearing segment was made solidly, but problems were experienced with a lack of roundness of the bore through the segment causing, on occasion, contact backout due to the lances of the contact becoming aligned with an out of round bore segment.
Another problem associated with housing of the prior art relates to the breakage or elongation of the sleeve due to muscle pulls. After the housing has been molded, the core pin can stick to the material of the sleeve, thereby causing the sleeve to be damaged as the core pin is removed. This is a frequent occurrence as the sleeve is not supported over its entire length. If the sleeve is torn or elongated, the contacts can not be properly seated and locked within the housing.
Accordingly, it is an object of the present invention to provide an improved electrical connector housing that facilitates an easy and reliable insertion of electrical contacts within the housing. It is a further object to provide a molded plastic housing having a beveled entry to facilitate guiding contacts during insertion with minimum distortion caused by unduly thick sections of plastic material surrounding the contact bearing segment. It is still a further object to provide a thermoplastic housing of molded material having a configuration facilitating high speed molding with minimum distortion and minimal muscle pulls.
It is a final object to provide a contact housing that includes interior beveling or tapering to facilitate contact entry and at the same time, a housing geometry facilitating high speed molding with minimum plastic distortion.